As known, switching devices are conceived for connecting/disconnecting parts of the electrical circuits into which they are installed.
To this aim, a switching device comprises at least one electrical phase, or pole, having a movable contact and a corresponding fixed contact. The movable contact can be actuated between a close position, in which it is coupled to the corresponding fixed contact in order to realize a conductive path for a current flowing through the phase, and an open position in which it is separated from the corresponding fixed contact in order to interrupt the conductive path.
The switching device comprises driving means and a kinematic chain for transmitting a force applied by the driving means to each one of its movable contacts. In particular, the driving means are adapted to drive the kinematic chain between a first operative position and a second operative position in order to actuate the movable contact relative to the corresponding fixed contact.
According to known solutions, the switching device further comprises control means for controlling the driving of the kinematic chain and, hence, the actuation of the movable contacts between the close and open positions. An example of a known switching device of this type is disclosed in the European patent application EP2523203.
The close position and the open position reached by the movable contacts must be kept until a further switching operation is required, even if one of these close and open positions is not energetically stable per se.
In other words, an undesired displacement of the movable contact from the close position to the open position or from the open position to the close position, such as displacements caused by disturbance forces applied to the kinematic chain, e.g. electromagnetic forces, vibrations and gravity, must be avoided.
If the control means and the driving means are properly supplied during the operation of the switching device, the control means control the driving means for adjusting undesired movements of the movable contact away from the reached close position or open position.
However, an undesired movement of the movable contact from the close position to the open position, or vice versa, must also be prevented in the case in that the control means and/or the driving means are not properly supplied. This critical condition can occur in the case of a fault power loss in a power supply associable to and suitable for operating the switching device.
For this reason, latching mechanisms are known in the art which are adapted to:                operatively interact with the kinematic chain in its first operative position or in its second operative position, in order to latch the movable contacts in the reached close position or open position; and        disengage the kinematic chain when a further switching operation is required.        
Such latching mechanisms are complex, expensive and bulky.
Hence, at the current state of the art, although known solutions perform in a rather satisfying way, there is still reason and desire for further improvements.